The reward, part of the department's "Rewards for Justice" program, has been in effect since January of this year.

The department's decision to publicize the reward, which was
previously shrouded in privacy due to concerns that its disclosure might
jeopardize efforts to apprehend those responsible for the attack, came
after lawmakers fretted that the State Department was not using every
available tool to bring the perpetrators to justice.

"Due to security issues and sensitivities surrounding the
investigation, the event-specific reward offer has not been publicly
advertised on the [Rewards for Justice] website," a statement from the
State Department explained. "The confirmation of an award offer was
included today in the Department's response to an October 30, 2013
letter to Secretary Kerry from House Homeland Security Committee
Chairman Michael McCaul and eighty-two additional members of Congress."

A State Department official familiar with the matter tells CBS News
the reward is for information leading to an arrest - not for dead
bodies. It applies to any individual linked to Benghazi and not just
those cited on the FBI website seeking information about the
perpetrators.

The $10 million benchmark is the second highest level of reward offered by the program.

On September 11, 2012, then-U.S. Ambassador to Libya Chris Stevens
and three other Americans were slain when an armed mob attacked a U.S.
facility in Benghazi, Libya. Despite U.S. attempts to investigate and
prosecute those responsible, the perpetrators remain at large.

CBS News Senior National Security Analyst Juan Zarate has described
the difficulty inherent in U.S. efforts to identify those responsible
and stage a raid to apprehend them. "There are risks to any of these
operations. It creates a lot of tension internally, because you are, in
some ways, going after the sovereignty of the country," he said.

Moreover, he added, "There's a question as to whether or not we've
got the complete picture on who was responsible for Benghazi."

"You want to go in in a way that not only is successful, but has
maximum impact, and to my mind, that means grabbing as many of the
perpetrators as possible, or at least knowing who you're going after in a
definitive way," he explained. "I'm not sure we're there yet in terms
of the investigation, and that may be a reason why you haven't seen
further action in Benghazi."